Art of rolling metal plates.



T. H. MATHIAS.

ART OF ROLLING METAL PLATES. APPLICATION FILED SEPT. 16, 1904.

PATENTED JUNE 12, 1906.

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No. 823,345. PATENTED JUNE 12, 1906 T. H. MATHIAS. ART OF ROLLING METAL PLATES.

APPLICATION FILED SEPT. 16, 1904.

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UNITED STATES PATENT OFFICE.

THOMAS H. MATHIAS,

OF CHICAGO, ILLINOIS, ASSIGNOR TO ILLINOIS Specification of Letters. Patent.

Patented June 12,1906.

Application filed September 16,!1904. Serial No. 224,657.

T at whom it may concern.-

Be it known that I, THOMAS H. MATHIAS, of Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in the Art of Rolling Metal Plates,

' of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

It is the usual practice in the manufacture of rolled plates-such as shiplates, tankplates, boiler-plates, and the ike-to first roll the ingots into slabs of rectangular crosssection, these slabs being subsequently reheated and transferred to the plate-mill, where they are rolled into plates of the desired dimensions. In rolling plates of considerable width, such as those fifty inches wide and upward, the plates on leaving the rolls show a fish-tail shape to such an extent that they may vary from twenty to thirty inches in length between the center and the ends, thereby causing a considerable percentage of loss in trimmings or plate scrap. This fish-tailing is due to the spring in the rolls, which causes the plate to be thinner at the sides than at the middle and causes a dislacement or squeezing of the metal at the ateral portions of the plate toward its ends, the result being that the plate becomes longer at the sides than at the middle. The fishtail ends of the plate are also hard on the rolls, as they become chilled and hard.

My invention is desi ned to provide an improved method of rol ing plates which will prevent the formation of these fish-tail ends, thereby reducing very largely the percentage of plate scrap and increasing the plate percentage. My new method by preventing. the formation of fish-tails also greatly relieves the rolls by providing better plate ends upon which theycan get a square bite across the entire width of the late. These objects I accomplish in the fol owing manner.

In the first place I depart from the usual practice of employing rectangular slabs of substantially uniform thickness throughout and instead I roll a slab of symmetrical crosssection in which the lateral portions are thinner than the central portion throughout the len th of the slab. I then reheat this slab an transfer it to the plate-mill having plain cylindrio rolls, where it is first rolled in the passed through the same direction that it rolls of the slabbing-mill. The result of this rolling is to cause the thicker metal at the longitudinal central portion of the slab to flow toward the ends of the plate, so that after being passed several times through the rolls in this direction the ends of the late are of convex form-that is to say, t e plate is longer on its middle line than at its lateral edges. The plate is now turned and passed a number of times through the rolls a dl rection at'right angles to the directlon m which the slab was rolled. This operation gives the plate the requisite width, but still leaves the plate longer along its middle line than at the edges, taking such middle line through the plate in a direction arallel to that in which the slab was rol ed. This cross-rolling also very considerably increases the tensile stren th and elastic limit of the finished plate. T e plate is now again turned and rolled in the same direction as at first to the proper thickness or gage. The effect of this last rolling is to cause the metal at the lateral portions of the plate to flow in the directionof the rolling faster than the metal at the central portion, due to the spring of the rolls, while the metal at the central portion tends to be squeezed or displaced toward the lateral portions, the finalresult being the formation of a late whoseends are approximately straigfit and in which the waste to be trimmed isreduced to a minimum.

In the accompanying drawings, Figure 1 1s a view showing the character of rolls employed in the slabbing-mill for the purpose of rolling the slabs; Fig. 2, a perspective view of one of the slabs; 3, a cross-section of the same; Fig. 4, a p an. view showing a proximately the shape of the plate after't e first step in rolling; Fig. 5, a similar view showing the ap roximate form of the plate after the secon rolling, and Fig. 6 a similar 'vieW of the plate as it finally leaves the rolls.

The slab A leaves the finishing-pass b of the slabbing-rolls B in the form shown in Figs. 2 and 3that is to say, with its lateral portions a thinner than its central portionthe reduction in thickness being at both the upper and the lower surfaces of the slab, which is preferably of symmetrical cross-section.

dimensions of the plates to be rolled. In a slab of thirty-six inches in Width, which under the old practice would be of a uniform thickness of five inches, I find it advisable to increase the thickness to about five and one-half inches at the central portion for somewhat more than one-half the total Width 'of the slab and then to gradually taper down to a thickness of five inches, which 1s held to its lateral ed es. These figures and the precise section 1 lustrated in the drawings are, however, merely illustrative and may be considerably varied, the essential feature being in every case to provide an excess of metal at the central over the lateral portions of the slab sufficient to take care of the displacement described,.and this is a matter which the experienced roller can readily determine by observation. I do not, therefore, limit myself to the use of a slab of the particular section shown and described.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. The art or method of rolling metal plates, which consists informing a slab havin an excess of metal at its longitudinal centra portion, then rolling said slab first in the direction of its length and second, at ri ht angles to such direction, and finally rolling the shape (produced by the preceding steps in the same irection as at first, the last two rolling operations being with lain cylindrical rolls.

2. The art or met a 0d of rolling metal lates, which consists first forming a slab avin an excess of metal at its longitudinal centra portion but of the same cross-section throughout its length, then rerolling said slab first the direction ofits length, then at right angles to the first rerolling, and finally, in the same direction as at first, the first and second rerolling operations being with lain cylindrical rolls, for the urposes descri ed.

In testimony whereo I have aflixed my signature in presence of two witnesses.

THOMAS H. MATHIAS. 

